Session: SE-09-01 Advanced Seismic Evaluation and Code

Paper Number: 61905

Start Time: Tuesday, July 13, 2021, 08:00 PM

61905 - Micro Ultrasonic Knurling Technology Creating High Precision Texture on Sliding Surface in Mechanical System (Fundamental Experiment) 

Sliding surface in mechanical system is required to move smoothly and stop at target position. Sliding surface can move and stop by applying adequate friction force. Friction force is controlled by developing technology creating small texture on the surface with a few to a few hundred micrometer intervals. If friction force is reduced by applying this technology to large area sliding surface of generators, machine tools and so on, the machining effect is drastically improved. It is necessary to develop machining technology to create texture with high precision and efficiency.

On the other hand, ultrasonic vibration is used in many manufacturing fields. It is well known that surface roughness is improved and stress is reduced using ultrasonic vibration. In this study, machining technology is developed creating wear resistant texture on large area sliding surface with high precision and efficiency using ultrasonic vibration during knurling.

In this paper, the effect of ultrasonic vibration on knurling is examined by the fundamental experiment. In this study, tools are pressed on the workpiece. Ultrasonic vibration is applied in the direction of pressing during knurling. This technology is named as Micro Ultrasonic Knurling : MUK.

The technology can be applied to the dampers and the base isolation systems for reduction of seismic response of the structures. In some of those devices, friction characteristics are an important factor for controlling their efficiency. Seismic response of the structures is reduced to apply adequate friction force.

First, a horn to amplify ultrasonic vibration is designed and made. Horn is designed to transmit vibration of Langevin-type transducer to surface of workpiece efficiently. Frequency response function is measured after making horn. It is found that desired frequency is available.

Second, small grooves are created by an indenter on the surface of workpiece using ultrasonic vibration in the experiment. Workpiece is fixed by bolts on the feed table. The indenter is pressed in vertical direction, workpiece is fed in lateral direction and grooves are created. The indenter is set at the tip of horn. Ultrasonic vibration is applied during creating grooves. A three dimensional dynamometer is set under workpiece to measure pressing force and friction force for various target depth of groove. As a result, those forces are reduced using ultrasonic vibration for all target depth of groove. Distribution of depth is measured and profile curve and waviness curve are obtained. Groove is deeper and wider using ultrasonic vibration.

Third, in order to examine the effectiveness of MUK, a processing machine using the 3-axis feed table is designed and made. A workpiece is fixed on the table by bolts through a piezoelectric three-dimensional dynamometer. The pressing tool with texture is fixed by bolts in the tip of holder. An experiment is made using specimens with extra super duralumin (JIS, A7075P) and copper (JIS, C1100P). Pressing force is fixed. Surface of the specimen is observed. Processing marks are measured on whole range of machining. For the specimen made of extra super duralumin, clear marks are formed in wider range when ultrasonic vibration is used during knurling. The groove is enlarged, deeper and clearer marks are formed. For the specimen made of copper, clear marks are also formed in wider range when ultrasonic vibration is used during knurling. For both specimens, processing efficiency is improved using ultrasonic vibration during knurling. The effect of ultrasonic vibration for the specimen made of copper is larger than that made of copper. It is necessary to use appropriate ultrasonic vibration depending on material.

Presenting Author: Shigeru Aoki Tokyo Metropolitan College of Industrial Technology

Authors:

Shigeru Aoki Tokyo Metropolitan College of Industrial Technology
Yasunori Sakai Shibaura Institute of Technology
Tomohisa Tanaka Tokyo Institute of Technology